Fibers, and particularly organic fibers, often require heat treatment to develop certain properties. Rayon fibers or fibers of polyaerylonitrile or polyacrylonitrile, for example, may be converted to a conductive (carbonaceous) form through high-temperature treatment. Heat is also employed in the drying of coatings or dyes upon a variety of synthetic or natural fibers.
Various ovens have been developed for the heat treatment of fibers. The fibers commonly are supported on rolls or spools, and such ovens may be provided with a device at one end for unrolling and feeding a length of fibers into the oven, and a take-up roller or spool at the other end of the oven for winding up the heated length of fibers. In some ovens, the fibers make several passes through the oven and rollers or spools are located at each end of the oven to collect the fibers exiting the oven and redirect them to the oven for another pass. Many entry and exit points through the oven wall are required in these embodiments.